Many plant species bear fruits that suggest adaptation to seed dispersal by extinct megafauna. Present-day seed dispersal of these megafaunal plants is carried out by rodents, which can act as predators or dispersers; whether this interaction is primarily positive or negative can depend on the context. Here, we parameterized a stochastic model using data from the field and experimental arenas to estimate the effect of rodents on the recruitment of Myrcianthes coquimbensis -an Atacama Desert shrub with megafaunal fruits- and examine whether environmental conditions can alter the sign and strength of these rodent-plant interactions. We show that the outcome of these interactions is context-dependent: in wet conditions seed removal by rodents negatively impacts the recruitment probability of M. coquimbensis; in contrast, in dry conditions, the interaction with rodents increases recruitment success. In all cases, the strength of the effect of rodents on the recruitment success was determined mainly by their role as dispersers, which could be positive or negative. This study demonstrates that by caching seeds, rodents can be effective dispersers of a megafaunal fruit plant, but that the sign and magnitude of their effect on recruitment changes as a function of the environmental context in which the interaction occurs.

许多植物物种结出果实，表明已灭绝的大型动物适应了种子的传播。目前，这些大型真菌植物的种子传播是通过啮齿动物来进行的，它们可以充当捕食者或传播者。这种交互作用主要是正面的还是负面的可以取决于上下文。在这里，我们使用来自野外和实验场所的数据对随机模型进行参数化，以评估啮齿动物对募集Myrcianthes coquimbensis（一种带有大型动物果实的阿塔卡马沙漠灌木）的影响，并研究环境条件是否可以改变这些啮齿动物的体征和强度-植物相互作用。我们表明，这些相互作用的结果是取决于上下文的：在潮湿的环境中，啮齿动物去除种子会负面影响种子的募集概率。柯氏藻; 相反，在干燥条件下，与啮齿动物的相互作用增加了募集成功。在所有情况下，啮齿类动物对招聘成功的影响力主要取决于它们作为分散剂的作用，可能是正面的也可能是负面的。这项研究表明，通过缓存种子，啮齿动物可以成为大型真菌植物的有效分散剂，但是它们对募集的影响的迹象和程度随发生相互作用的环境而变化。